Foot Controlled Phaser

[Red_special_21]

hey everybody,

i'm very new to making effect pedals (actually i'm just about to start making a Treble Booster then moving onto a Chorus pedal)

i'm a Big Brian May fan and so i want some effects so i can get close to his sound, now i could go out and buy the individual effects or buy the Digitech Brian May pedal. But ive decided against this as you cant experiment or alter the individual effects in the pedal, and also being a student and being poor most of the time ive decided to attempt to build them.

as i said before i'm about to make a treble booster and then a chorus pedal, the last effect pedal on my list is a Foxx Foot Phaser now there currently going for £150 to £200 so i definatly cant afford one of those,

so i thought i would ask you guys for your expert opinion to answer these 3 questions.

1) What would be the best Phase effect clone to choose to make?
2) Could you put a expression wah pedal on it?
3) And how would i do this?

all advice would be grateful
thanks

[Mark Hammer]

A 1978 issue of POLYPHONY has a nice little foot-controlled phaser circuit.  I'll need to scan and post it.  Essentially, it is a plain vanilla FET-based phaser with a rather conventional (by analog synth standards, anyways) CV input stage to feed the FET gates.  A "range/offset" control is included that feeds a DC bias to the CV mixer, suppposedly in tandem with whatever LFO or envelope source you want to feed it.

Actually, one thing I've always wanted but never really knew enough about to do it myself was a CV mixer stage to insert between the LFO and OTA stages in either the Small Stone or Ross phasers.  It would be nice to have the option of tuning the initial point in the sweep or having some sort of envelope-controlled phasing, in addition to the stock LFO sweeping.  Being able to combine multiple LFOs for a less periodic sweep would be nice too.

[snoof]

I'd like to see that Mark, if you ever get it scanned.  I've never dealt with anything CV related before...

[widdly]

Actually, one thing I've always wanted but never really knew enough about to do it myself was a CV mixer stage to insert between the LFO and OTA stages in either the Small Stone or Ross phasers.  It would be nice to have the option of tuning the initial point in the sweep or having some sort of envelope-controlled phasing, in addition to the stock LFO sweeping.  Being able to combine multiple LFOs for a less periodic sweep would be nice too.

That would be awesome. Combining a foot pedal sweep input with the Univibe mods would make for a crazy pedal.  If you added an envelope follower and the LPF cap mod you could do an auto-wah as well.  Sort of like two of the mooger foogers in one pedal.

This page might be of interest...
http://hem.bredband.net/bersyn/vcp.htm

It's a modular synth voltage controlled phaser based on a small stone

[Mark Hammer]

Here's Tom Gamble's attempt to do that very deed.  Assume the OTA stages are either LM13600 or CA3094